package tdd

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/mathiasbq/supervisor/internal/brain"
	"github.com/mathiasbq/supervisor/internal/session"
)

func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error) {
	switch tool {
	case "tdd_red":
		return s.handleRed(ctx, args)
	case "tdd_green":
		return s.handleGreen(ctx, args)
	case "tdd_refactor":
		return s.handleRefactor(ctx, args)
	default:
		return nil, fmt.Errorf("unknown tool: %s", tool)
	}
}

type redArgs struct {
	ProjectRoot string `json:"project_root"`
	Spec        string `json:"spec"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
}

func (s *Skill) handleRed(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args redArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.Spec == "" {
		return nil, fmt.Errorf("spec is required")
	}
	brainCtx, _ := brain.Query(ctx, s.cfg.IngestBaseURL, args.Spec, 3)

	task := fmt.Sprintf(
		"phase: red\nproject_root: %s\nspec: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.Spec, s.resolveModel(args.Model), args.TestCmd,
	)
	if brainCtx != "" {
		task = brainCtx + "\n---\n\n" + task
	}
	return s.complete(ctx, s.resolveModel(args.Model), task)
}

type greenArgs struct {
	ProjectRoot string `json:"project_root"`
	TestPath    string `json:"test_path"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
	SessionID   string `json:"session_id"`
}

func (s *Skill) handleGreen(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args greenArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.TestPath == "" {
		return nil, fmt.Errorf("test_path is required")
	}
	task := fmt.Sprintf(
		"phase: green\nproject_root: %s\ntest_path: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.TestPath, s.resolveModel(args.Model), args.TestCmd,
	)
	task = session.PrependHistory(s.cfg.SessionsDir, args.SessionID, "green", task)

	t0 := time.Now()
	result, err := s.complete(ctx, s.resolveModel(args.Model), task)
	if err != nil {
		return nil, err
	}
	s.logEntry(args.SessionID, args.ProjectRoot, "tdd", "green", s.resolveModel(args.Model), t0, result)
	return result, nil
}

type refactorArgs struct {
	ProjectRoot string `json:"project_root"`
	TestPath    string `json:"test_path"`
	ImplPath    string `json:"impl_path"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
	SessionID   string `json:"session_id"`
}

func (s *Skill) handleRefactor(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args refactorArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.TestPath == "" {
		return nil, fmt.Errorf("test_path is required")
	}
	if args.ImplPath == "" {
		return nil, fmt.Errorf("impl_path is required")
	}
	task := fmt.Sprintf(
		"phase: refactor\nproject_root: %s\ntest_path: %s\nimpl_path: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.TestPath, args.ImplPath, s.resolveModel(args.Model), args.TestCmd,
	)
	task = session.PrependHistory(s.cfg.SessionsDir, args.SessionID, "refactor", task)

	t0 := time.Now()
	result, err := s.complete(ctx, s.resolveModel(args.Model), task)
	if err != nil {
		return nil, err
	}
	s.logEntry(args.SessionID, args.ProjectRoot, "tdd", "refactor", s.resolveModel(args.Model), t0, result)
	return result, nil
}

func (s *Skill) resolveModel(override string) string {
	if override != "" {
		return override
	}
	return s.cfg.DefaultModel
}

// complete calls CompleteFunc and returns the text as JSON.
func (s *Skill) complete(ctx context.Context, model, task string) (json.RawMessage, error) {
	if s.cfg.CompleteFunc == nil {
		return nil, fmt.Errorf("no executor configured")
	}
	text, dur, err := s.cfg.CompleteFunc(ctx, model, s.cfg.SkillPrompt, task)
	if err != nil {
		return nil, err
	}
	return json.Marshal(map[string]any{"text": text, "model": model, "duration_ms": dur})
}

// logEntry writes a session.Entry for a completed phase if session_id is set.
func (s *Skill) logEntry(sessionID, projectRoot, skill, phase, model string, t0 time.Time, raw json.RawMessage) {
	if sessionID == "" || s.cfg.SessionsDir == "" {
		return
	}
	var msg string
	var result struct {
		Text string `json:"text"`
	}
	if err := json.Unmarshal(raw, &result); err == nil && len(result.Text) > 0 {
		msg = result.Text
		if len(msg) > 200 {
			msg = msg[:200]
		}
	}
	_ = session.Append(s.cfg.SessionsDir, sessionID, session.Entry{
		SessionID:   sessionID,
		Timestamp:   time.Now(),
		Skill:       skill,
		Phase:       phase,
		ProjectRoot: projectRoot,
		FinalStatus: "ok",
		ModelUsed:   model,
		DurationMs:  time.Since(t0).Milliseconds(),
		Message:     msg,
	})
}