package tide

import (
	"context"
	"fmt"
	"strings"
)

// ReplayFlow executes each recorded step against target and diffs responses.
func ReplayFlow(ctx context.Context, flow Flow, cfg ReplayConfig) (Result, error) {
	if err := validateFlow(flow); err != nil {
		return Result{}, err
	}
	if strings.TrimSpace(cfg.Target) == "" {
		return Result{}, fmt.Errorf("tide: replay target is required")
	}
	client := cfg.Client
	if client == nil {
		client = defaultClient()
	}
	limit := maxBody(cfg.MaxBody)
	store := cfg.Store
	if store == nil {
		store = mustMemoryStore()
	}
	result := Result{OK: true, Steps: make([]StepResult, 0, len(flow.Steps))}
	skipRest := false
	for _, step := range flow.Steps {
		if skipRest {
			result.Steps = append(result.Steps, StepResult{ID: step.ID, Skipped: true})
			continue
		}
		sr := StepResult{ID: step.ID, OK: true}
		want := step
		if err := materializeSidecar(cfg.BaseDir, &want.Response); err != nil {
			return result, fmt.Errorf("tide: replay step %s: %w", step.ID, err)
		}
		req, err := expandRequest(step.Request, store)
		if err != nil {
			sr.OK = false
			result.OK = false
			sr.Diffs = append(sr.Diffs, Diff{Path: "request", Expected: "resolved placeholders", Actual: err.Error()})
			result.Steps = append(result.Steps, sr)
			skipRest = true
			continue
		}
		got, err := doStep(ctx, client, cfg.Target, req, limit)
		if err != nil {
			return result, fmt.Errorf("tide: replay step %s: %w", step.ID, err)
		}
		live := step
		live.Request = req
		live.Response = got
		if err := CaptureStep(store, &live); err != nil {
			sr.OK = false
			result.OK = false
			sr.Diffs = append(sr.Diffs, Diff{Path: "capture", Expected: "captured value", Actual: err.Error()})
			result.Steps = append(result.Steps, sr)
			skipRest = true
			continue
		}
		_ = ScrubStep(store, &live)
		sr.Diffs = append(sr.Diffs, compareStep(want, live.Response)...)
		if len(sr.Diffs) > 0 {
			sr.OK = false
			result.OK = false
		}
		result.Steps = append(result.Steps, sr)
	}
	if !result.OK {
		return result, &MismatchError{Result: result}
	}
	return result, nil
}

func mustMemoryStore() *Store {
	s, _ := OpenStore("")
	return s
}

func compareStep(want Step, got Response) []Diff {
	var diffs []Diff
	if want.Response.Status != 0 && got.Status != want.Response.Status {
		diffs = append(diffs, Diff{
			Path:     "status",
			Expected: fmt.Sprintf("%d", want.Response.Status),
			Actual:   fmt.Sprintf("%d", got.Status),
		})
	}
	diffs = append(diffs, compareHeaders(want.Response.Headers, got.Headers, want.Headers)...)
	diffs = append(diffs, compareBodies(want.Response, got, want)...)
	return diffs
}