Refactored, added comprehensive testing.

config/config.go

@@ -0,0 +1,141 @@
+package config
+
+import (
+	"fmt"
+	"os"
+)
+
+const UsageText = `Usage: aicli [OPTION]...
+Send prompts and files to LLM chat endpoints.
+
+Global:
+  --version                display version and exit
+
+Input:
+  -f, --file PATH          input file (repeatable)
+  -F, --stdin-file         treat stdin as file content
+  -p, --prompt TEXT        prompt text (repeatable)
+  -pf, --prompt-file PATH  read prompt from file
+
+System:
+  -s, --system TEXT        system prompt text
+  -sf, --system-file PATH  read system prompt from file
+                           (error if both -s and -sf provided)
+
+API:
+  -l, --protocol PROTO     openai or ollama (default: openai)
+  -u, --url URL            endpoint (default: https://api.ppq.ai/chat/completions)
+  -k, --key KEY            API key
+  -kf, --key-file PATH     read API key from file
+
+Models:
+  -m, --model NAME         primary model (default: gpt-4o-mini)
+  -b, --fallback NAMES     comma-separated fallback list (default: gpt-4.1-mini)
+
+Output:
+  -o, --output PATH        write to file (mode 0644) instead of stdout
+  -q, --quiet              suppress progress messages
+  -v, --verbose            log debug information to stderr
+
+Config:
+  -c, --config PATH        YAML config file
+
+Environment Variables:
+  AICLI_API_KEY            API key
+  AICLI_API_KEY_FILE       path to API key file
+  AICLI_PROTOCOL           API protocol
+  AICLI_URL                endpoint URL
+  AICLI_MODEL              primary model name
+  AICLI_FALLBACK           comma-separated fallback models
+  AICLI_SYSTEM             system prompt text
+  AICLI_SYSTEM_FILE        path to system prompt file
+  AICLI_CONFIG_FILE        path to config file
+  AICLI_PROMPT_FILE        path to prompt file
+  AICLI_DEFAULT_PROMPT     override default prompt
+
+Precedence Rules:
+  API key:      --key > --key-file > AICLI_API_KEY > AICLI_API_KEY_FILE > config key_file
+  System:       --system > --system-file > AICLI_SYSTEM > AICLI_SYSTEM_FILE > config system_file
+  Config file:  --config > AICLI_CONFIG_FILE
+  All others:   flags > environment > config file > defaults
+
+Stdin Behavior:
+  No flags:     stdin becomes the prompt
+  With -p/-pf:  stdin appends after explicit prompts
+  With -F:      stdin becomes first file (path: "input")
+
+Examples:
+  echo "What is Rust?" | aicli
+  cat log.txt | aicli -F -p "Find errors in this log"
+  aicli -f main.go -p "Review this code"
+  aicli -c ~/.aicli.yaml -f src/main.go -f src/util.go -o analysis.md
+  aicli -p "Context:" -pf template.txt -p "Apply to finance sector"
+`
+
+func printUsage() {
+	fmt.Fprint(os.Stderr, UsageText)
+}
+
+// BuildConfig resolves configuration from all sources with precedence:
+// flags > env > file > defaults
+func BuildConfig(args []string) (ConfigData, error) {
+	flags, err := parseFlags(args)
+	if err != nil {
+		return ConfigData{}, fmt.Errorf("parse flags: %w", err)
+	}
+
+	// Validate protocol strings before merge
+	if flags.protocol != "" && flags.protocol != "openai" && flags.protocol != "ollama" {
+		return ConfigData{}, fmt.Errorf("invalid protocol: must be openai or ollama, got: %s", flags.protocol)
+	}
+
+	configPath := flags.config
+	if configPath == "" {
+		configPath = os.Getenv("AICLI_CONFIG_FILE")
+	}
+
+	env := loadEnvironment()
+
+	// Validate env protocol
+	if env.protocol != "" && env.protocol != "openai" && env.protocol != "ollama" {
+		return ConfigData{}, fmt.Errorf("invalid protocol: must be openai or ollama, got: %s", env.protocol)
+	}
+
+	file, err := loadConfigFile(configPath)
+	if err != nil {
+		return ConfigData{}, fmt.Errorf("load config file: %w", err)
+	}
+
+	// Validate file protocol
+	if file.protocol != "" && file.protocol != "openai" && file.protocol != "ollama" {
+		return ConfigData{}, fmt.Errorf("invalid protocol: must be openai or ollama, got: %s", file.protocol)
+	}
+
+	cfg := mergeSources(flags, env, file)
+
+	if err := validateConfig(cfg); err != nil {
+		return ConfigData{}, err
+	}
+
+	return cfg, nil
+}
+
+// IsVersionRequest checks if --version flag was passed
+func IsVersionRequest(args []string) bool {
+	for _, arg := range args {
+		if arg == "--version" {
+			return true
+		}
+	}
+	return false
+}
+
+// IsHelpRequest checks if -h or --help flag was passed
+func IsHelpRequest(args []string) bool {
+	for _, arg := range args {
+		if arg == "-h" || arg == "--help" {
+			return true
+		}
+	}
+	return false
+}