package llm

import "errors"

var (
	// ErrNoToolsConfigured is returned when the model requests tool calls but no tools are available.
	ErrNoToolsConfigured = errors.New("model requested tool calls but no tools configured")

	// ErrToolNotFound is returned when a requested tool is not in the toolbox.
	ErrToolNotFound = errors.New("tool not found")

	// ErrNotConnected is returned when trying to use an MCP server that isn't connected.
	ErrNotConnected = errors.New("MCP server not connected")

	// ErrStreamClosed is returned when trying to read from a closed stream.
	ErrStreamClosed = errors.New("stream closed")

	// ErrNoStructuredOutput is returned when the model did not return a structured output tool call.
	ErrNoStructuredOutput = errors.New("model did not return structured output")

	// ErrAliasLoop is returned when alias resolution exceeds the maximum depth (10),
	// indicating a cycle such as "a" → "b" → "a".
	ErrAliasLoop = errors.New("alias resolution loop detected (depth > 10)")

	// ErrUnknownProvider is returned when a spec references a provider name that
	// is not registered and has no corresponding LLM_X environment variable.
	ErrUnknownProvider = errors.New("unknown provider")

	// ErrInvalidDSN is returned when a DSN string (from an LLM_X env var) cannot
	// be parsed. Expected format: scheme://[token@]host[/path].
	ErrInvalidDSN = errors.New("invalid DSN")
)