package render

import (
	"encoding/json"
	"fmt"
	"io"

	"github.com/kotoyuuko/zenmux-usage-cli/internal/api"
)

// jsonAccountEntry is the shape of each element in multi-account JSON mode.
type jsonAccountEntry struct {
	Account string    `json:"account"`
	Success bool      `json:"success"`
	Data    *api.Data `json:"data"`
	Error   *string   `json:"error"`
}

// RenderJSONSingle writes the raw API body to w with a trailing newline.
// Used when exactly one account was resolved — preserves the exact shape
// returned by the API so `jq .data.plan.tier` keeps working.
func RenderJSONSingle(w io.Writer, raw []byte) error {
	if _, err := w.Write(raw); err != nil {
		return err
	}
	if len(raw) == 0 || raw[len(raw)-1] != '\n' {
		if _, err := w.Write([]byte{'\n'}); err != nil {
			return err
		}
	}
	return nil
}

// RenderJSONMulti emits an ordered JSON array with one object per result.
// Successful entries have data populated and error: null; failed entries
// have data: null and a non-empty error message.
func RenderJSONMulti(w io.Writer, results []AccountResult) error {
	out := make([]jsonAccountEntry, len(results))
	for i, r := range results {
		entry := jsonAccountEntry{Account: r.Name}
		switch {
		case r.Err != nil:
			entry.Success = false
			msg := r.Err.Error()
			entry.Error = &msg
		case r.Response == nil:
			entry.Success = false
			msg := "no response"
			entry.Error = &msg
		default:
			entry.Success = r.Response.Success
			entry.Data = &r.Response.Data
			if !r.Response.Success {
				msg := r.Response.Error
				if msg == "" {
					msg = "api returned success=false"
				}
				entry.Error = &msg
				entry.Data = nil
			}
		}
		out[i] = entry
	}
	enc := json.NewEncoder(w)
	enc.SetIndent("", "  ")
	if err := enc.Encode(out); err != nil {
		return fmt.Errorf("encode multi-account json: %w", err)
	}
	return nil
}