package run

// steps.go — the per-run step emitter and the tool→step presentation
// mapping. This is the single place that turns the executor's two loop
// chokepoints (the pre-dispatch tool hook + the post-step observer in
// executor.go) into ordered tool.Step records: one per tool call,
// each with a stable id, an open-vocabulary kind, and a human
// present-tense summary that flips running→complete/error.
//
// One source feeds two consumers (mirroring the OnEvent/OnToolEvent/
// PostRunResult pattern): the live tool.Invocation.OnStep callback
// (nil-safe) AND snapshot(), which the executor copies onto Result.Steps.
// Because the Result accumulation does not depend on OnStep being set,
// every surface — chat (JSON + SSE), Discord, cron, sub-agents — carries
// steps; OnStep is needed only for live streaming.

import (
	"context"
	"encoding/json"
	"fmt"
	"net/url"
	"strings"
	"time"

	"gitea.stevedudenhoeffer.com/steve/majordomo/llm"

	"gitea.stevedudenhoeffer.com/steve/executus/tool"
)

// stepSummaryMaxLen caps the human summary length (section G size cap).
// Detail is unused in v1 (no live detail source while replies are
// generated blocking) so there is no Detail cap yet.
const stepSummaryMaxLen = 200

// stepEmitter accumulates ordered steps for one run and fires the live
// OnStep callback.
//
// Concurrency: touched ONLY from the agent-loop goroutine. Both call
// sites (the hookToolbox `before` closure and the stepObserver) run
// there; majordomo executes a step's tool calls sequentially, and
// sub-agents build their own Invocation so they never reach this
// emitter. Same single-goroutine contract as the audit Writer and the
// critic ProgressRecorder — no internal lock.
type stepEmitter struct {
	onStep func(ctx context.Context, ev tool.StepEvent)
	now    func() time.Time

	seq     int
	steps   []tool.Step   // ordered; the snapshot for Result.Steps
	byID    map[string]int      // step id -> index into steps
	pending map[string][]string // correlation key -> queued running ids (FIFO)
}

// newStepEmitter returns an emitter that forwards to onStep (nil-safe).
func newStepEmitter(onStep func(ctx context.Context, ev tool.StepEvent)) *stepEmitter {
	return &stepEmitter{
		onStep:  onStep,
		now:     time.Now,
		byID:    map[string]int{},
		pending: map[string][]string{},
	}
}

// corrKey correlates a "start" (name + raw args, no call id available at
// the pre-dispatch hook) with its later "end" (the stepObserver has the
// full call incl. id + the same raw args).
func corrKey(name string, args json.RawMessage) string {
	return name + "\x00" + string(args)
}

// toolStart records + emits the "start" of a tool call. Called from the
// pre-dispatch hookToolbox closure, before the tool runs.
func (e *stepEmitter) toolStart(ctx context.Context, name string, args json.RawMessage) {
	if e == nil {
		return
	}
	step := e.newStep(name, args)
	key := corrKey(name, args)
	e.pending[key] = append(e.pending[key], step.ID)
	e.fire(ctx, "start", step)
}

// toolEnd records + emits the terminal "end" of a tool call. Called from
// the stepObserver for each completed tool call. If no matching start was
// seen (e.g. a tool with a nil handler the pre-dispatch hook skipped), a
// start is synthesized so the step still appears.
func (e *stepEmitter) toolEnd(ctx context.Context, call llm.ToolCall, result string, isError bool) {
	if e == nil {
		return
	}
	id := e.matchPending(call.Name, call.Arguments)
	if id == "" {
		id = e.newStep(call.Name, call.Arguments).ID
	}
	idx, ok := e.byID[id]
	if !ok {
		return
	}
	step := &e.steps[idx]
	end := e.now()
	step.EndedAt = &end
	if isError {
		step.Status = "error"
	} else {
		step.Status = "complete"
	}
	if s := summaryForEnd(call.Name, call.Arguments, result, isError); s != "" {
		step.Summary = s
	}
	e.fire(ctx, "end", *step)
}

// newStep mints + appends a running step and returns it (by value).
func (e *stepEmitter) newStep(name string, args json.RawMessage) tool.Step {
	e.seq++
	step := tool.Step{
		ID:        fmt.Sprintf("s%d", e.seq),
		Kind:      kindForTool(name),
		Title:     name,
		Summary:   summaryForStart(name, args),
		Status:    "running",
		StartedAt: e.now(),
	}
	e.byID[step.ID] = len(e.steps)
	e.steps = append(e.steps, step)
	return step
}

// matchPending pops the oldest running step id for (name, args). Falls
// back to the most recent still-running step of the same tool name when
// the args don't byte-match between start and end. Returns "" on no match.
func (e *stepEmitter) matchPending(name string, args json.RawMessage) string {
	key := corrKey(name, args)
	if q := e.pending[key]; len(q) > 0 {
		id := q[0]
		if len(q) == 1 {
			delete(e.pending, key)
		} else {
			e.pending[key] = q[1:]
		}
		return id
	}
	for i := len(e.steps) - 1; i >= 0; i-- {
		if e.steps[i].Title == name && e.steps[i].Status == "running" {
			return e.steps[i].ID
		}
	}
	return ""
}

func (e *stepEmitter) fire(ctx context.Context, phase string, step tool.Step) {
	if e.onStep == nil {
		return
	}
	e.onStep(ctx, tool.StepEvent{Phase: phase, Step: step})
}

// snapshot returns a copy of the ordered, deduplicated step set for the
// run Result. A step still "running" at run end (e.g. the run was
// cancelled mid-tool-call) is reported as-is.
func (e *stepEmitter) snapshot() []tool.Step {
	if e == nil || len(e.steps) == 0 {
		return nil
	}
	out := make([]tool.Step, len(e.steps))
	copy(out, e.steps)
	return out
}

// kindForTool maps a tool name to an open-vocabulary step kind. Unknown
// tools fall back to "tool" — never an error, just a generic step (the
// client maps unknown kinds to a default icon). Loosely tracks the
// catalog in pkg/skilltools/CLAUDE.md.
func kindForTool(name string) string {
	switch name {
	case "web_search", "search_reddit", "wikipedia_summary":
		return "search"
	case "read_page", "read_pdf", "read_reddit", "read_video", "verify_url",
		"summary_summarise", "summarize", "file_get_text", "file_get_metadata",
		"http_get", "http_post", "http_get_stream", "http_stream_read":
		return "read"
	case "code_exec", "calculate":
		return "code"
	case "file_save", "file_get", "file_list", "file_delete", "file_search":
		return "file"
	case "kv_get", "kv_set", "kv_list", "kv_delete",
		"remember", "recall", "chatbot_get_memories":
		return "memory"
	case "query", "query_research", "deepresearch", "animate",
		"agent_invoke", "agent_invoke_parallel", "agent_spawn",
		"agent_spawn_parallel", "skill_invoke", "skill_invoke_parallel":
		return "delegate"
	case "think":
		return "thinking"
	default:
		switch {
		case strings.HasPrefix(name, "image") || strings.Contains(name, "draw"):
			return "image"
		default:
			return "tool"
		}
	}
}

// summaryForStart builds the human present-tense running summary. It
// derives specifics from safe arg fields only; secret-bearing tools
// (mcp_call, email_send, http_*) are summarized without echoing args.
func summaryForStart(name string, args json.RawMessage) string {
	var s string
	switch name {
	case "web_search":
		if q := argString(args, "query", "q"); q != "" {
			s = fmt.Sprintf("Searching the web for %q", q)
		} else {
			s = "Searching the web"
		}
	case "search_reddit":
		if q := argString(args, "query", "q"); q != "" {
			s = fmt.Sprintf("Searching Reddit for %q", q)
		} else {
			s = "Searching Reddit"
		}
	case "wikipedia_summary":
		if q := argString(args, "query", "title"); q != "" {
			s = fmt.Sprintf("Looking up %q on Wikipedia", q)
		} else {
			s = "Looking up Wikipedia"
		}
	case "read_page", "read_pdf", "read_reddit", "read_video", "verify_url":
		if u := argString(args, "url", "post", "page"); u != "" {
			s = "Reading " + hostOf(u)
		} else {
			s = "Reading a page"
		}
	case "http_get", "http_post", "http_get_stream":
		// Show host only — a full URL can embed credentials/tokens.
		if u := argString(args, "url"); u != "" {
			s = "Fetching " + hostOf(u)
		} else {
			s = "Making an HTTP request"
		}
	case "summary_summarise", "summarize":
		s = "Summarizing text"
	case "translate":
		if lang := argString(args, "target_lang", "target_language", "lang"); lang != "" {
			s = "Translating to " + lang
		} else {
			s = "Translating text"
		}
	case "code_exec":
		s = "Running code"
	case "calculate":
		if q := argString(args, "query", "expression", "expr"); q != "" {
			s = "Calculating " + truncateStep(q, 60)
		} else {
			s = "Calculating"
		}
	case "remember":
		// Never echo the stored value.
		s = "Saving a memory"
	case "recall", "chatbot_get_memories":
		s = "Recalling memories"
	case "kv_get", "kv_list":
		s = "Reading saved data"
	case "kv_set":
		s = "Saving data"
	case "kv_delete":
		s = "Deleting saved data"
	case "file_save":
		if n := argString(args, "name", "filename"); n != "" {
			s = "Saving file " + truncateStep(n, 60)
		} else {
			s = "Saving a file"
		}
	case "file_get", "file_get_text", "file_get_metadata":
		s = "Reading a file"
	case "file_list", "file_search":
		s = "Listing files"
	case "query", "query_research":
		if q := argString(args, "query", "question", "prompt", "task"); q != "" {
			s = "Researching " + truncateStep(q, 80)
		} else {
			s = "Researching"
		}
	case "deepresearch":
		s = "Running deep research"
	case "animate":
		s = "Generating an animation"
	case "agent_invoke", "agent_spawn":
		if a := argString(args, "agent", "agent_name", "name"); a != "" {
			s = "Delegating to " + a
		} else {
			s = "Delegating to a sub-agent"
		}
	case "agent_invoke_parallel", "agent_spawn_parallel":
		s = "Delegating to sub-agents"
	case "skill_invoke":
		if sk := argString(args, "skill_name", "skill", "name"); sk != "" {
			s = "Running skill " + sk
		} else {
			s = "Running a skill"
		}
	case "skill_invoke_parallel":
		s = "Running skills in parallel"
	case "think":
		s = "Thinking"
	case "mcp_call":
		// Redact: MCP args frequently carry secrets. Name server/tool only.
		srv, tl := argString(args, "server"), argString(args, "tool")
		switch {
		case srv != "" && tl != "":
			s = fmt.Sprintf("Calling %s/%s", srv, tl)
		case srv != "":
			s = "Calling " + srv
		default:
			s = "Calling an MCP tool"
		}
	case "email_send":
		// Redact recipients + body.
		s = "Sending an email"
	default:
		s = "Using " + name
	}
	return truncateStep(s, stepSummaryMaxLen)
}

// summaryForEnd optionally upgrades the summary to a cheap result phrase.
// Returns "" to keep the running summary (the caller then just flips the
// status). Never returns a phrase derived from raw result bytes.
func summaryForEnd(name string, _ json.RawMessage, result string, isError bool) string {
	if isError {
		return ""
	}
	switch name {
	case "web_search", "search_reddit":
		if n := countResults(result); n >= 0 {
			return fmt.Sprintf("Found %d result%s", n, plural(n))
		}
	}
	return ""
}

// argString pulls the first present non-empty string field from a tool's
// raw JSON args, trying keys in order. Returns "" when none parse.
func argString(args json.RawMessage, keys ...string) string {
	if len(args) == 0 {
		return ""
	}
	var m map[string]any
	if err := json.Unmarshal(args, &m); err != nil {
		return ""
	}
	for _, k := range keys {
		if v, ok := m[k]; ok {
			if s, ok := v.(string); ok && strings.TrimSpace(s) != "" {
				return strings.TrimSpace(s)
			}
		}
	}
	return ""
}

// countResults parses a v11-style {"results":[...]} envelope and returns
// the count, or -1 when the shape doesn't match.
func countResults(result string) int {
	if strings.TrimSpace(result) == "" {
		return -1
	}
	var env struct {
		Results []json.RawMessage `json:"results"`
	}
	if err := json.Unmarshal([]byte(result), &env); err != nil || env.Results == nil {
		return -1
	}
	return len(env.Results)
}

// hostOf returns the bare host (no leading www.) of a URL, or a short
// form of the raw string when it doesn't parse as a URL.
func hostOf(raw string) string {
	if u, err := url.Parse(raw); err == nil && u.Host != "" {
		return strings.TrimPrefix(u.Host, "www.")
	}
	return truncateStep(raw, 60)
}

// truncateStep rune-safely caps s to max, appending an ellipsis when cut.
func truncateStep(s string, max int) string {
	if max <= 0 {
		return ""
	}
	r := []rune(s)
	if len(r) <= max {
		return s
	}
	if max == 1 {
		return string(r[:1])
	}
	return string(r[:max-1]) + "…"
}

func plural(n int) string {
	if n == 1 {
		return ""
	}
	return "s"
}