package messages

import (
	"encoding/json"
	"fmt"
	"strings"
)

// BuildStatus represents the status of a build response.
type BuildStatus string

const (
	BuildStatusStarted   BuildStatus = "started"
	BuildStatusProgress  BuildStatus = "progress"
	BuildStatusCompleted BuildStatus = "completed"
	BuildStatusFailed    BuildStatus = "failed"
	BuildStatusRejected  BuildStatus = "rejected"
)

// IsFinal returns true if this status indicates a terminal state.
func (s BuildStatus) IsFinal() bool {
	switch s {
	case BuildStatusCompleted, BuildStatusFailed, BuildStatusRejected:
		return true
	default:
		return false
	}
}

// BuildRequest is the message sent to request a build.
type BuildRequest struct {
	Repo    string `json:"repo"`              // Must match config
	Target  string `json:"target"`            // Hostname or "all"
	Branch  string `json:"branch,omitempty"`  // Optional, uses repo default
	ReplyTo string `json:"reply_to"`
}

// Validate checks that the request is valid.
func (r *BuildRequest) Validate() error {
	if r.Repo == "" {
		return fmt.Errorf("repo is required")
	}
	if !revisionRegex.MatchString(r.Repo) {
		return fmt.Errorf("invalid repo name format: %q", r.Repo)
	}
	if r.Target == "" {
		return fmt.Errorf("target is required")
	}
	// Target must be "all" or a valid hostname (same format as revision/branch)
	if r.Target != "all" && !revisionRegex.MatchString(r.Target) {
		return fmt.Errorf("invalid target format: %q", r.Target)
	}
	if r.Branch != "" && !revisionRegex.MatchString(r.Branch) {
		return fmt.Errorf("invalid branch format: %q", r.Branch)
	}
	if r.ReplyTo == "" {
		return fmt.Errorf("reply_to is required")
	}
	// Validate reply_to format to prevent publishing to arbitrary subjects
	if !strings.HasPrefix(r.ReplyTo, "build.responses.") {
		return fmt.Errorf("invalid reply_to format: must start with 'build.responses.'")
	}
	return nil
}

// Marshal serializes the request to JSON.
func (r *BuildRequest) Marshal() ([]byte, error) {
	return json.Marshal(r)
}

// UnmarshalBuildRequest deserializes a request from JSON.
func UnmarshalBuildRequest(data []byte) (*BuildRequest, error) {
	var r BuildRequest
	if err := json.Unmarshal(data, &r); err != nil {
		return nil, fmt.Errorf("failed to unmarshal build request: %w", err)
	}
	return &r, nil
}

// BuildHostResult contains the result of building a single host.
type BuildHostResult struct {
	Host            string  `json:"host"`
	Success         bool    `json:"success"`
	Error           string  `json:"error,omitempty"`
	DurationSeconds float64 `json:"duration_seconds"`
}

// BuildResponse is the message sent in response to a build request.
type BuildResponse struct {
	Status  BuildStatus `json:"status"`
	Message string      `json:"message,omitempty"`

	// Progress updates
	Host           string `json:"host,omitempty"`
	HostSuccess    *bool  `json:"host_success,omitempty"`
	HostsCompleted int    `json:"hosts_completed,omitempty"`
	HostsTotal     int    `json:"hosts_total,omitempty"`

	// Final response
	Results              []BuildHostResult `json:"results,omitempty"`
	TotalDurationSeconds float64           `json:"total_duration_seconds,omitempty"`
	Succeeded            int               `json:"succeeded,omitempty"`
	Failed               int               `json:"failed,omitempty"`

	Error string `json:"error,omitempty"`
}

// NewBuildResponse creates a new response with the given status and message.
func NewBuildResponse(status BuildStatus, message string) *BuildResponse {
	return &BuildResponse{
		Status:  status,
		Message: message,
	}
}

// WithError adds an error message to the response.
func (r *BuildResponse) WithError(err string) *BuildResponse {
	r.Error = err
	return r
}

// Marshal serializes the response to JSON.
func (r *BuildResponse) Marshal() ([]byte, error) {
	return json.Marshal(r)
}

// UnmarshalBuildResponse deserializes a response from JSON.
func UnmarshalBuildResponse(data []byte) (*BuildResponse, error) {
	var r BuildResponse
	if err := json.Unmarshal(data, &r); err != nil {
		return nil, fmt.Errorf("failed to unmarshal build response: %w", err)
	}
	return &r, nil
}